drm_vblank_get
int drm_vblank_get(struct drm_device *dev, unsigned int pipe);
return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
ret = drm_vblank_get(dev, pipe);
ret = drm_vblank_get(dev, pipe);
ret = drm_vblank_get(dev, vblank->pipe);